Increasing genetic variability in common wheat by utilization of alien cytoplasms - Cytoplasmic effects on the performance and interplant variability of the F1 and F2 generations of the cross, Triticum aestivum cv. Chinese Spring*cv. Norin 61.

Using eu- and alloplasmic lines of a common wheat cultivar, Chinese Spring, and euplasmic line of cv. Norin 61, the effects of four fertile cytoplasms derived from Aegilops squarrosa, Ae. speltoides, Ae. kotschyi and Ae. vavilovii on the performance and interplant variability of 13 agronomic characters in the F1 and F2 generations of the cross between Chinese Spring and Norin 61 were investigated. The performances and interplant variabilities of both generations were little affected by any of the alien cytoplasms, but sterility increased slightly by the vavilcvii cytoplasm in the F2 generation. Transgressive segregation attributable to the nucleus × cytoplasm interaction could not be detected in the present F2, in contrast with some positive transgressive segregation observed in the F2 of the cross between two related cultivars, Norin 61 and Norin 26, under the presence of the speltoides and kotschyi cytoplasms (TSUNEWAKI et al. 1985). Neither the heterosis nor the heritability in a broad sense was affected significantly by any alien cytoplasm. The present and previous results suggest that new common wheat genotypes better adapted to an alien cytoplasm than to the wheat cytoplasm might be created step by step, using the hybrids between closely rather than distantly related cultivars.